The efficacy of guava (Psidiumguajava L.) leaf extract on some bacterial isolates from milk

Pathogenic bacteria isolated from cow milk represent play a major role in mastitis and are not easy to treat even with the use of a wide range of antibacterial agents. Finding alternative substances that may eliminate those bacteria with less side effects especially if they are derived from natural sources. Here, guava (Psidiumguajava L.) leaf extracts (GLE) of six solvents; n-hexane (HGLE), methanol (MGLE), ethanol (EGLE), ethyl acetate (EtGLE), and chloroform (CGLE) were used to evaluate their Mueller-Hinton-II based inhibition activities against Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia, Staphylococcus aureus, Salmonella spp. (isolated from milk of local cows in the current work). The results showed that the CGLE was highly effective in decreasing the growth of the selected bacteria, followed by, EtGLE, MGLE, and EGLE when compared with the ciprofloxacin control. The findings revealed that HGLE did not show any activity in inhibiting those bacteria. The present study presents promising compounds for treating mastitis caused by these bacteria; however, clinical trials showed be performed to estimate their therapeutic doses, safety, and effectiveness.